	Computational Chemistry Comparison and Benchmark DataBase Release 22 (May 2022) Standard Reference Database 101 National Institute of Standards and Technology
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All results from a given calculation for Si₂H₄ (Disilene)

using model chemistry: BLYP/aug-cc-pVTZ

19 10 17 12 22

States and conformations

State	Conformation	minimum conformation	conformer description	state description
1	1	no	D2H	¹A_G
1	2	yes	C2H	¹A_G
1	3	no	C2V	¹A₁

Conformer 1 (D2H)

Jump to S1C2 S1C3

Energy calculated at BLYP/aug-cc-pVTZ

	hartrees
Energy at 0K	-581.329019
Energy at 298.15K
HF Energy	-581.329019
Nuclear repulsion energy	78.311012

The energy at 298.15K was derived from the energy at 0K and an integrated heat capacity that used the calculated vibrational frequencies.

Vibrational Frequencies calculated at BLYP/aug-cc-pVTZ

Mode Number	Symmetry	Frequency (cm^-1)	Scaled Frequency (cm^-1)	IR Intensities (km mol^-1)	Raman Act (Å⁴/u)	Dep P	Dep U
1	A_g	2196	2189	0.00	419.63	0.13	0.24
2	A_g	917	914	0.00	20.66	0.17	0.29
3	A_g	564	562	0.00	117.76	0.12	0.22
4	A_u	529	527	0.00	0.00	0.00	0.00
5	B_1u	2191	2184	60.36	0.00	0.00	0.00
6	B_1u	841	838	111.76	0.00	0.00	0.00
7	B_2g	276i	275i	0.00	23.20	0.75	0.86
8	B_2u	2231	2223	96.92	0.00	0.00	0.00
9	B_2u	345	344	17.98	0.00	0.00	0.00
10	B_3g	2219	2212	0.00	221.68	0.75	0.86
11	B_3g	581	579	0.00	4.37	0.75	0.86
12	B_3u	490	489	0.02	0.00	0.00	0.00

Unscaled Zero Point Vibrational Energy (zpe) 6413.9 cm^-1
Scaled (by 0.9966) Zero Point Vibrational Energy (zpe) 6392.1 cm^-1
See section III.C.1 List or set vibrational scaling factors to change the scale factors used here.
See section III.C.2 Calculate a vibrational scaling factor for a given set of molecules to determine the least squares best scaling factor.

Rotational Constants (cm^-1) from geometry optimized at BLYP/aug-cc-pVTZ

A	B	C
2.65585	0.21335	0.19749

See section I.F.4 to change rotational constant units

Geometric Data calculated at BLYP/aug-cc-pVTZ

Point Group is D_2h

Cartesians (Å)

Atom	y (Å)	z (Å)
Si1	0.000	1.077
Si2	0.000	-1.077
H3	1.255	1.868
H4	-1.255	1.868
H5	1.255	-1.868
H6	-1.255	-1.868

Atom - Atom Distances (Å)

	Si1	Si2	H3	H4	H5	H6
Si1		2.1547	1.4833	1.4833	3.2018	3.2018
Si2	2.1547		3.2018	3.2018	1.4833	1.4833
H3	1.4833	3.2018		2.5096	3.7366	4.5011
H4	1.4833	3.2018	2.5096		4.5011	3.7366
H5	3.2018	1.4833	3.7366	4.5011		2.5096
H6	3.2018	1.4833	4.5011	3.7366	2.5096

picture of Disilene state 1 conformation 1

More geometry information
Calculated Bond Angles

atom1	atom2	atom3	angle	atom1	atom2	atom3	angle
Si1	Si2	H5	122.225	Si1	Si2	H6	122.225
Si2	Si1	H3	122.225	Si2	Si1	H4	122.225
H3	Si1	H4	115.549	H5	Si2	H6	115.549

Electronic energy levels

Charges, Dipole, Quadrupole and Polarizability
Charges from optimized geometry at BLYP/aug-cc-pVTZ Charges (e)

Number	Element	Mulliken
1	Si	0.317
2	Si	0.317
3	H	-0.158
4	H	-0.158
5	H	-0.158
6	H	-0.158

Electric dipole moments
Electric dipole components in Debye
(What's a Debye? See section VII.A.3)

	x	y	z	Total
	0.000	0.000	0.000	0.000
CHELPG
AIM
ESP

Electric Quadrupole moment
Quadrupole components in D Å

Primitive
	x	y	z
x	-31.955	0.000	0.000
y	0.000	-29.611	0.000
z	0.000	0.000	-28.001

Traceless
	x	y	z
x	-3.149	0.000	0.000
y	0.000	0.367	0.000
z	0.000	0.000	2.782

Polar
3z²-r²	5.564
x²-y²	-2.344
xy	0.000
xz	0.000
yz	0.000

Polarizabilities
Components of the polarizability tensor.
Units are Å³ (Angstrom cubed)
Change units.

	x	y	z
x	9.922	0.000	0.000
y	0.000	9.267	0.000
z	0.000	0.000	15.493

<r²> (average value of r²) Å²

<r²>	71.406
(<r²>)^1/2	8.450

Conformer 2 (C2H)

Jump to S1C1 S1C3

Energy calculated at BLYP/aug-cc-pVTZ

	hartrees
Energy at 0K	-581.331006
Energy at 298.15K
HF Energy	-581.331006
Nuclear repulsion energy	77.357002

The energy at 298.15K was derived from the energy at 0K and an integrated heat capacity that used the calculated vibrational frequencies.

Vibrational Frequencies calculated at BLYP/aug-cc-pVTZ

Mode Number	Symmetry	Frequency (cm^-1)	Scaled Frequency (cm^-1)	IR Intensities (km mol^-1)	Raman Act (Å⁴/u)	Dep P	Dep U
1	A_g	2152	2145	0.00	471.00	0.15	0.26
2	A_g	925	922	0.00	21.30	0.25	0.40
3	A_g	536	534	0.00	83.29	0.11	0.20
4	A_g	355	354	0.00	16.04	0.46	0.63
5	A_u	2185	2177	142.74	0.00	0.00	0.00
6	A_u	499	497	0.01	0.00	0.00	0.00
7	A_u	333	332	15.73	0.00	0.00	0.00
8	B_g	2172	2165	0.00	261.22	0.75	0.86
9	B_g	596	594	0.00	3.98	0.75	0.86
10	B_u	2150	2142	120.09	0.00	0.00	0.00
11	B_u	901	898	175.67	0.00	0.00	0.00
12	B_u	402	401	26.58	0.00	0.00	0.00

Unscaled Zero Point Vibrational Energy (zpe) 6602.7 cm^-1
Scaled (by 0.9966) Zero Point Vibrational Energy (zpe) 6580.3 cm^-1
See section III.C.1 List or set vibrational scaling factors to change the scale factors used here.
See section III.C.2 Calculate a vibrational scaling factor for a given set of molecules to determine the least squares best scaling factor.

Rotational Constants (cm^-1) from geometry optimized at BLYP/aug-cc-pVTZ

A	B	C
2.45756	0.20710	0.19438

See section I.F.4 to change rotational constant units

Geometric Data calculated at BLYP/aug-cc-pVTZ

Point Group is C_2h

Cartesians (Å)

Atom	x (Å)	y (Å)	z (Å)
Si1	0.000	1.098	0.000
Si2	0.000	-1.098	0.000
H3	0.477	1.796	1.229
H4	0.477	1.796	-1.229
H5	-0.477	-1.796	1.229
H6	-0.477	-1.796	-1.229

Atom - Atom Distances (Å)

	Si1	Si2	H3	H4	H5	H6
Si1		2.1963	1.4919	1.4919	3.1805	3.1805
Si2	2.1963		3.1805	3.1805	1.4919	1.4919
H3	1.4919	3.1805		2.4588	3.7165	4.4563
H4	1.4919	3.1805	2.4588		4.4563	3.7165
H5	3.1805	1.4919	3.7165	4.4563		2.4588
H6	3.1805	1.4919	4.4563	3.7165	2.4588

picture of Disilene state 1 conformation 2

More geometry information
Calculated Bond Angles

atom1	atom2	atom3	angle	atom1	atom2	atom3	angle
Si1	Si2	H5	117.893	Si1	Si2	H6	117.893
Si2	Si1	H3	117.893	Si2	Si1	H4	117.893
H3	Si1	H4	110.988	H5	Si2	H6	110.988

Electronic energy levels

Charges, Dipole, Quadrupole and Polarizability
Charges from optimized geometry at BLYP/aug-cc-pVTZ Charges (e)

Number	Element	Mulliken
1	Si	0.281
2	Si	0.281
3	H	-0.140
4	H	-0.140
5	H	-0.140
6	H	-0.140

Electric dipole moments
Electric dipole components in Debye
(What's a Debye? See section VII.A.3)

	x	y	z	Total
	0.000	0.000	0.000	0.000
CHELPG
AIM
ESP

Electric Quadrupole moment
Quadrupole components in D Å

Primitive
	x	y	z
x	-31.657	-0.567	0.000
y	-0.567	-28.298	0.000
z	0.000	0.000	-30.022

Traceless
	x	y	z
x	-2.497	-0.567	0.000
y	-0.567	2.541	0.000
z	0.000	0.000	-0.045

Polar
3z²-r²	-0.090
x²-y²	-3.359
xy	-0.567
xz	0.000
yz	0.000

Polarizabilities
Components of the polarizability tensor.
Units are Å³ (Angstrom cubed)
Change units.

	x	y	z
x	9.651	-0.414	0.000
y	-0.414	15.930	0.000
z	0.000	0.000	9.302

<r²> (average value of r²) Å²

<r²>	72.359
(<r²>)^1/2	8.506

Conformer 3 (C2V)

Jump to S1C1 S1C2

Energy calculated at BLYP/aug-cc-pVTZ

	hartrees
Energy at 0K	-581.297413
Energy at 298.15K
HF Energy	-581.297413
Nuclear repulsion energy	72.040995

The energy at 298.15K was derived from the energy at 0K and an integrated heat capacity that used the calculated vibrational frequencies.

Vibrational Frequencies calculated at BLYP/aug-cc-pVTZ

Mode Number	Symmetry	Frequency (cm^-1)	Scaled Frequency (cm^-1)	IR Intensities (km mol^-1)	Raman Act (Å⁴/u)	Dep P	Dep U
1	A₁	2008	2001	349.39	288.90	0.27	0.42
2	A₁	1564	1559	0.13	65.37	0.06	0.12
3	A₁	854	851	20.77	81.84	0.18	0.31
4	A₁	368	367	0.27	43.34	0.43	0.60
5	A₁	362	361	0.77	11.74	0.05	0.10
6	A₂	1294	1289	0.00	0.30	0.75	0.86
7	A₂	608	606	0.00	0.27	0.75	0.86
8	B₁	1213	1208	24.87	0.24	0.75	0.86
9	B₁	789	786	15.13	3.80	0.75	0.86
10	B₂	1983	1976	14.51	49.15	0.75	0.86
11	B₂	1279	1275	915.74	36.66	0.75	0.86
12	B₂	701	699	70.32	0.06	0.75	0.86

Unscaled Zero Point Vibrational Energy (zpe) 6511.6 cm^-1
Scaled (by 0.9966) Zero Point Vibrational Energy (zpe) 6489.4 cm^-1
See section III.C.1 List or set vibrational scaling factors to change the scale factors used here.
See section III.C.2 Calculate a vibrational scaling factor for a given set of molecules to determine the least squares best scaling factor.

Rotational Constants (cm^-1) from geometry optimized at BLYP/aug-cc-pVTZ

A	B	C
2.51672	0.15842	0.15488

See section I.F.4 to change rotational constant units

Geometric Data calculated at BLYP/aug-cc-pVTZ

Point Group is C_2v

Cartesians (Å)

Atom	x (Å)	y (Å)	z (Å)
Si1	0.000	1.340	-0.092
Si2	0.000	-1.340	-0.092
H3	-1.029	0.000	-0.150
H4	1.029	0.000	-0.150
H5	0.000	1.371	1.436
H6	0.000	-1.371	1.436

Atom - Atom Distances (Å)

	Si1	Si2	H3	H4	H5	H6
Si1		2.6802	1.6907	1.6907	1.5277	3.1121
Si2	2.6802		1.6907	1.6907	3.1121	1.5277
H3	1.6907	1.6907		2.0584	2.3357	2.3357
H4	1.6907	1.6907	2.0584		2.3357	2.3357
H5	1.5277	3.1121	2.3357	2.3357		2.7427
H6	3.1121	1.5277	2.3357	2.3357	2.7427

picture of Disilene state 1 conformation 3

More geometry information
Calculated Bond Angles

atom1	atom2	atom3	angle	atom1	atom2	atom3	angle
Si1	Si2	H5	29.393	Si1	Si2	H6	91.172
Si2	Si1	H3	37.569	Si2	Si1	H4	37.569
H3	Si1	H4	74.995	H5	Si2	H6	61.780

Electronic energy levels

Charges, Dipole, Quadrupole and Polarizability
Charges from optimized geometry at BLYP/aug-cc-pVTZ Charges (e)

Number	Element	Mulliken
1	Si	0.097
2	Si	0.097
3	H	0.013
4	H	0.013
5	H	-0.109
6	H	-0.109

Electric dipole moments
Electric dipole components in Debye
(What's a Debye? See section VII.A.3)

	x	y	z	Total
	0.000	0.000	0.275	0.275
CHELPG
AIM
ESP

Electric Quadrupole moment
Quadrupole components in D Å

Primitive
	x	y	z
x	-27.704	0.000	0.000
y	0.000	-31.864	0.000
z	0.000	0.000	-33.786

Traceless
	x	y	z
x	5.121	0.000	0.000
y	0.000	-1.119	0.000
z	0.000	0.000	-4.002

Polar
3z²-r²	-8.004
x²-y²	4.160
xy	0.000
xz	0.000
yz	0.000

Polarizabilities
Components of the polarizability tensor.
Units are Å³ (Angstrom cubed)
Change units.

	x	y	z
x	8.366	0.000	0.000
y	0.000	15.152	0.000
z	0.000	0.000	10.115

<r²> (average value of r²) Å²

<r²>	80.004
(<r²>)^1/2	8.944

All results from a given calculation for Si2H4 (Disilene)

using model chemistry: BLYP/aug-cc-pVTZ

States and conformations

Conformer 1 (D2H)

Conformer 2 (C2H)

Conformer 3 (C2V)

All results from a given calculation for Si₂H₄ (Disilene)